He L, Liu C, Chen S, Zhang J, Gao M, Li L. Precursor-directed production of water-soluble red
Monascus pigments with high thermal stability via azaphilic addition reaction-based semi-synthesis.
Food Chem X 2023;
20:100940. [PMID:
38144809 PMCID:
PMC10739767 DOI:
10.1016/j.fochx.2023.100940]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/02/2023] [Accepted: 10/09/2023] [Indexed: 12/26/2023] Open
Abstract
Red Monascus pigments (MPs) are a large group of polyketides from the fungus Monascus which have been widely used as food colorants. In this study, a variety of red MPs congeners were prepared to explore promising water-soluble candidates for application in liquid food formulations. The results showed that by combining the two-stage, low-pH fermentation strategy with a downstream purification step of fractional crystallization, precursors of red MPs, namely monascorubrin and rubropunctatin, were obtained with a purity of 91.9%. Then, via the azaphilic addition reaction, 18 types of red MPs congeners carrying different amino acid moieties (MPs-aa) were semi-synthesized. Compared to rubropunctamine and monascorubramine, the water solubility, pH and thermal stability of MPs-aa were improved greatly. MPs-His, MPs-Phe, MPs-Tyr and MPs-Trp were identified to be the most resistant to pasteurization. These findings provide water-soluble red MPs candidates with high thermal stability and an attractive approach for their large scale production.
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